Caption: MODEL RELEASED. Water purification tablets production. Tablet of sodium dichloroisocyanurate (NaDCC), or effervescent chlorine, being held in the gloved hand of a factory worker. These tablets produce chlorine when added to water, which has the effect of purifying the water and making it safe to drink. The tablets are highly effective in killing the microbes in contaminated water that cause dysentery, diarrhoea, cholera and other water-borne diseases. The tablets can be used against bacteria, bacterial spores, cysts, algae, fungi, protozoa and viruses. These tablets are being manufactured by the Scotmas company in Scotland. Photographed in 2016.